Chapter 5 Review
1. The figure below represents the probability distribution for selecting a number of
objects out of a container. Construct a probability distribution from this graph.
2. The number of song requests a radio station receives per day is indicated in the table
below. Construct a graph for this data.
8
9
10
11
12
Number of calls, x
0.21 0.31 0.16 0.14 0.18
Probability ,p(x)
3. For the following data, construct a graph showing the probability distribution.
p(x)
x
0
0.35
1
0.25
2
0.20
3
0.15
4
0.05
4. Why is the following distribution is not a probability distribution?
x
-5
-4
-3
-2
P(x)
0.19
0.16
–0.10
0.48
-1
0.27
5. What of the following pairs of probability values would complete the following
probability distribution?
x
-3
-2
-1
0
1
P(x)
0.09
0.21
p1
p2
0.17
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2
0.25
Chapter 5 Review
6. A multiple choice quiz consists of 7 questions, each with 3 possible answers. If a
student guesses at the answer to each question, then the mean number of correct answers
is what?
7. What probability value would be needed to complete the following probability
distribution?
x
-5
-1
0
1
4
P(x)
0.12
0.24
0.12
0.24
8. Find the mean and standard deviation of the distribution shown.
x
-3
-2
-1
P(x)
0.20
0.24
0.47
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0
0.09
Chapter 5 Review
Answer Key
1
2.
3.
4.
5.
6.
7.
8.
A probability is negative
p1= 0.02, p2 = 0.26
2.33
0.28
–1.55
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Chapter 5 Review
Additional Questions:
1) The mass function of a random variable X is given below
Value of X 1
P(X=x)
1.5 2
3
0.4 0.4 0.1
a. Complete the table.
b. Find the expected value of X.
c. What is the probability of getting at least a two?
d. Find the standard deviation of the random variable X.
2) A box contains two $1 bills, three $5 bills, one $10 bill, and three $20 bills.
Construct a probability distribution for the data.
3) A bank vice president feels that each savings account customer has, on
average, three credit cards. The following distribution represents the number of
credit cards people own. Find the mean, variance, and standard deviation. Is the
vice president correct?
4) A pizza shop owner determines the number of pizzas that are delivered each
day. Find the mean, variance, and standard deviation for the distribution shown. If
the manager stated that 45 pizzas were delivered on one day, do you think that
this is a believable claim?
5) A 35-year-old woman purchases a $100,000 term life insurance policy for an
annual payment of $360.
Based on a period life table for the U.S. government, the probability that she will
survive the year is
0.999057. Find the expected value of the policy for the insurance company.
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